ASDF

Meeting Minutes: ASDF Interim #5

Date: 2026-05-13 Participants: Hyunjeong Lee, Carsten Bormann, Rohit Mohan, Jungha Hong, Lorenzo Corneo, Ari Keränen, Bart Brinckman.

Summary

The ASDF Interim Meeting #5 focused on updating the modeling for digital twins and addressing feedback from the Working Group Last Call (WGLC) for the NIPC and Protocol Mapping documents. Major technical discussions centered on protocol binding consistency in NIPC and the integration of diverse communication protocols within the digital twin framework.

Key Discussion Points

1. Administrative and Agenda

Lorenzo Corneo opened the meeting and presented the chairs slides, including the Note Well and Code of Conduct. Ari Keränen volunteered to take notes.

2. Digital Twin Modeling

Jungha Hong presented SDF modeling for digital twin (revision -04), detailing updates to draft-ietf-asdf-digital-twin.

Protocol Considerations: The draft now includes Section 5, covering MQTT, CoAP, BLE, and NIPC. The focus is on how SDF provides the semantic model while protocols enable operational synchronization.
Discussion: Lorenzo Corneo noted that protocol mappings for all listed protocols are not yet standardized. Ari Keränen suggested adding an informational note to the draft clarifying that some protocols are for future consideration and are not yet fully supported by the current SDF specification to avoid implementer confusion. Jungha Hong agreed to add this clarification.
Future Work: The next steps involve extending the work to AI agent-based digital twins for autonomous control.

3. NIPC (Non-Internet-Connected Physical Components)

Bart Brinckman and Rohit Mohan discussed the latest updates to draft-ietf-asdf-nipc, specifically addressing review comments generated by an automated review tool provided by Ari Keränen.

Data Models: Fixed inconsistencies between text and CDDL regarding arrays vs. lists and updated examples in Section 8.
Query Parameters: The group reaffirmed the decision to use query parameters for identifiers (Data App ID, Instance ID) for consistency across the API.
Trigger Responses: Bart Brinckman explained that the difference in trigger responses between single devices and groups is intentional; group triggers must return device arrays since instance IDs are linked to the group.
Patch Support: The draft currently uses PUT for updates. Carsten Bormann noted that because SDF-ref is based on merge patch, adding PATCH support would be trivial. Bart Brinckman agreed to add text noting that while PUT is standard, PATCH with the appropriate media type could be supported in the future.
Timestamps: For the timestamp field, the group decided to stick to the definition of CBOR Tag 1 (epoch seconds) in the text while keeping the CDDL representation as a float for implementation simplicity.
BLE Flags: Added "indicator" and "write without response" flags to the BLE enum to align with existing specifications.
Polling vs. Pub-Sub: Bart Brinckman clarified that while the API supports polling, it also leverages callbacks/webhooks. A note will be added to ensure this is obvious to implementers.

4. SDF Protocol Mapping

Rohit Mohan provided a status update on draft-ietf-asdf-sdf-protocol-mapping.

Recent changes primarily involved formatting and line folding based on a PR from Carsten Bormann.
A new revision is expected shortly to address minor remaining open issues before the conclusion of WGLC.

5. Next Steps and Planning

WGLC Progression: Ari Keränen will perform a final cross-reference check between the NIPC specification and the OpenAPI definitions to ensure consistency.
IETF 120 (Vienna): Attendance will be mixed. Carsten Bormann, Bart Brinckman, and Lorenzo Corneo plan to attend. Ari Keränen can attend early in the week. Jungha Hong, Hyunjeong Lee, and Rohit Mohan noted they would likely be unable to attend in person.
Next Interim: Scheduling is on hold pending the submission of documents to the Area Director (AD). The chairs will request an review estimate from the AD before setting the next date.

Decisions and Action Items

Decision: Retain query parameters for all identifiers in draft-ietf-asdf-nipc to maintain API consistency.
Action Item (Bart Brinckman): Post the summarized review issue list (from the automated review) to the mailing list or GitHub, documenting the resolutions discussed.
Action Item (Rohit Mohan): Submit updated version of draft-ietf-asdf-sdf-protocol-mapping addressing pending minor issues.
Action Item (Ari Keränen): Complete OpenAPI cross-reference check for draft-ietf-asdf-nipc.
Action Item (Jungha Hong): Add a note to draft-ietf-asdf-digital-twin regarding the standardization status of listed protocols.

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